This invention relates in general to display controllers, and more specifically to a device for displaying color images on a screen of a cathode ray tube (CRT).
A particular application of this invention is the display of a bar indicator on a screen in two colors. A bar indicator, also known as a bar graph, is useful for graphical depiction of changing values of a continuous function.
Conventional bar graph displays have been limited in several respects. One type of bar graph uses only one color, where the bar is displayed in this one color against only an indistinct background, making it difficult for the viewer to distinguish clearly the current value of the function relative to its maximum value. A second type of bar graph uses more than one color, but the character information to be displayed is stored with its own color attribute, requiring additional memory. These and other disadvantages of the prior art are overcome by the present invention.